1. Field of the Invention
The present invention relates to method of routing a packet in a routing device, and more particularly, to a routing method being able to reduce the packet-processing time by setting a routing path that depends on the characteristic of each packet.
2. Discussion of the Related Art
In general, a device that connects two or more network systems having a same transmission protocol is often referred to as a routing device. A typical routing device included in a network system sets a node in the system itself or in another network system, and it transmits one or more packets received using a given transmission path.
FIG. 1 illustrates a network system including a typical routing device 10. The main processor 1 checks whether a packet is received through a port 6. When the routing device 10 receives a packet, whose destination address is set to another node or another routing device (e.g., R2), the main processor 1 sends the packet to the protocol layer 2 included in the routing device 10. The protocol layer 2 may be any one of the IP (Internet Protocol) layer 2A, IPX (Internetwork Packet exchange) layer 2B, Bridge layer 2C, and many others.
For example, when the IP layer 2A receives the packet from the main processor 1, it initially determines whether to process the packet. Once it decides to process the packet, the IP layer 2A sends the packets to the top application module 3.
On the other hand, if it decides not to process the packet, it checks the destination address of the packet. For example, the IP layer 2A obtains the interface number corresponding to the destination address of the packet by searching the IP routing table 4A of the routing table 4. And it sends the packets to the interface found. Then the packet gets transmitted to a node or routing device corresponding to the destination address of the packet.
As described above, the packet passes through a routing path that includes the main processor 1 and the IP layer 2A, and this is shown in FIG. 2. Since such routing path is formed regardless of the individual characteristic of the packet, the packet-processing rate of the routing device 10 is low. Therefore, the performance of the routing device may be degraded.
Even though it is highly desirable to provide a method of setting a routing path that depends on the individual characteristic of each packet, such method is currently unavailable for the existing routing device.